Various types of adjustable air outlet vents are known, for example as components of heating, ventilation and air-conditioning (HVAC) systems in residential and commercial buildings. Such air outlet vents may also be used in the HVAC systems of motor vehicles, aircraft, railroad cars, and the like. Such air outlet vents are to provide the desired air flow pattern, volume flow rate, and flow velocity for achieving a comfortable environment for persons occupying the building, vehicle, or the like in which the air outlet vents are installed. It is particularly important that the air outlet vents be adjustable, for adjusting the air distribution pattern, flow rate, and/or flow velocity when the vent is positioned relatively close to a location at which a person will be seated or standing, such as a work station. In these situations, it is important that the air flow characteristics can be adjusted to suit the affected person's preferences while simultaneously providing the required ventilation and heating or cooling.
An adjustable floor-mounted air outlet vent of the above mentioned general type is, for example, disclosed in German Patent 4,405,867. The known air outlet vent according to this German patent achieves the combined and adjustably selectable functions of a flooding source outlet that provides a gentle substantially horizontal flow into the space being ventilated, as well as a spiral or swirl outlet vent that provides a high energy swirling or spiralling vertical air flow into the space being ventilated. To achieve this, the cover plate of the air outlet vent includes two groups of radially elongated air outlet slots or slits, whereby the two groups of slits are respectively arranged on outer and inner concentric circles or partial circles. The two groups of air outlet slits respectively provide the two different air flow patterns described above.
To select the desired air flow pattern, the known air outlet vent further includes a control disk movably or adjustably arranged below the cover plate. Adjusting the height of the control disk partially or completely blocks the flow cross-sections of the air outlet slits belonging to the group arranged on the inner concentric circle, and thereby selectively adjusts the air flow pattern. All of the radially extending air outlet slits of each respective group are uniformly circumferentially distributed and have the same shape and size, and a uniform orientation. Furthermore, all of the slits are bounded by sidewalls that extend at a uniform angle relative to the vertical axis, so that the air emitted through these slits generates a spiralling or swirling air flow. While the known air outlet vent is very effective at incorporating the characteristics of a horizontal flooding flow outlet vent and of a vertical spiralling or swirling outlet vent, as alternatively selectable operating options, it does not allow the primary air flow direction to be adjusted about the central vertical axis of the air outlet vent.